HP-35s in Hex mode


I guess I'm not the first person trying to use the 35s to do hexadecimal arithmetic... But the thing is next to useless! Looking at the example of a simple addition (page 11-5 in the user's guide), why does the 35s require a hex terminator, i.e. three additional keystrokes after every number?

Once HEX mode is selected, couldn't they make it work this way:
1 2 F
E 9 A

This is just plain-vanilla RPN... In decimal mode, arithmetic operators (such as + - * /) terminate the number being entered before performing the operation. Why not in hex mode? Didn't anyone at HP test this before releasing the code to production?

Beats me.

Joel Setton.


Joel, it is well known that number bases were not implemented well on the 35s. It is what it is and will not likely change.


Try the 27s. In Hex mode, it provides soft keys for A-F. Effortless.


Right. I also have an HP-20S which is close to the 27s in this respect, but they are both (ewww...) algebraic. Ah, well.

Joel Setton


Get a 32sii (or 32s). The number base handling is nearly identical to the 20s, the only difference being you have to switch bases using a menu, which amounts to one extra keystroke.

That said, the 20s is a surprisingly capable machine, and you can do some rather interesting tricks with INPUT, SWAP, and LAST. For example, here's a MOD program that uses no storage registers:


Lack of RPN on the 27S is it's big drawback.

That aside, the ease-of-use is amazing. R-P conversions, base conversions, etc., are all very intuitive.

I think it's very under-appreciated.


Lack of RPN on the 27S is it's big drawback.

*IF* you are an RPN fanatic. Which I am not.

Well, I forgot to mention the 42s also has an excellent implementation, with soft keys for A-F. But as Dave pointed out, the 32sii method is pretty slick, too.


I think it's very under-appreciated.

Based on the prices that model usually commands, I'm going to have to disagree with you. :)

Possibly Related Threads…
Thread Author Replies Views Last Post
  Integration question and "RPN" mode comment Craig Thomas 16 5,739 12-05-2013, 02:32 AM
Last Post: Nick_S
  HP Prime: Recommendation for future RPN Program Mode BruceTTT 3 2,114 11-13-2013, 10:03 PM
Last Post: BruceTTT
  Program to change entry mode on Prime Michael de Estrada 3 1,852 10-28-2013, 10:13 AM
Last Post: Han
  Prime: Exam mode (possible duplicate after funny response first time) Paul Townsend (UK) 1 1,451 10-24-2013, 03:09 PM
Last Post: Tim Wessman
  Does RPN entry mode cause the Prime keyboard to lock up ? Michael de Estrada 14 4,661 10-22-2013, 06:27 PM
Last Post: John Colvin
  HP Prime: Edit integer in RPN mode plivesey 15 4,832 10-18-2013, 04:34 PM
Last Post: kris223
  Temporary User Mode Key Programs not working in RPN BruceTTT 7 2,657 10-14-2013, 01:46 PM
Last Post: BruceTTT
  HP Prime: MAKELIST in RPN mode? toml_12953 2 1,609 10-13-2013, 07:40 PM
Last Post: BruceH
  Low battery slow mode Marcel Samek 4 1,592 09-18-2013, 02:02 PM
Last Post: Harald
  HP Prime - How to STO in RPN mode? Javier Goizueta 10 2,651 08-18-2013, 10:24 PM
Last Post: Xavier A. (Brazil)

Forum Jump: